So, even though the better life expectancy (from a disc degradation perspective) looks attractive; the standards associated with Optical Media are changing so rapidly that I'd be concerned about having a system capable of reading those discs years down the road, even if they are still OK from a data degradation perspective.

I think people really exaggerate the problem of not being able to read current optical media in the future. This potential problem applies to any storage medium.

1. However, optical discs in our current format have become very popular, retain backward compatibility and are not going to disappear any time soon. Even if blu-ray is not used in 50 years there is high likelihood it will be read by whatever next generation players are available then. Even if general public moves entirely to some other non-optical medium there will have been enough optical discs produced by humankind to sustain the demand for optical drives. If there is demand the production will continue, even if it is a niche market.

2. We must not forget that technology moves forwards and not backwards, which means that in 50, 100, 200 years building an optical reader will not be difficult at all and will be considered very easy and basic engineering. Who knows, it's possible there will be consumer grade scanners that you can buy for peanuts that will be able to scan and read all your dvds and blu-rays in a few seconds.

3. Even if optical storage were bound to disappear completely into oblivion this process will not happen overnight and everybody will have many long years to move the data to whatever next generation technology is available.

Archival storage will always be in demand by a certain minority. If m-disc proves to be successful enough I suppose we may never see a complete disappearance of optical media (within the next century or two) just because there will always be a small group of people in demand of archival media. M-disc may evolve in larger capacities and with keeping backward compatibility the working drives will live on.

I know there have been storage formats that are almost extinct now and hardly readable by anything but it hardly applies to blu-ray at the moment. Facebook is building large backup machines comprised of blu-ray discs because they prove to be a cost-effective solution.

As long as the disc will last 1000 years there's no need to worry about readability and for now we can relax knowing the data is safe. If we see any signs of optical drive extinction sometime in the future we can slowly transition to new media and we will have plenty of time for that.